Ultralight Self-Leveling Form Stake

ABSTRACT

A form stake having a narrow vertical shank body terminating at its upper end in a wider, flat driving shelf whose outer ends extend far enough from the shank body to provide grasping or hooking surfaces on the underside of the driving shelf spaced from the shank. At least a rearmost edge or surface of the shank is aligned flush with the rearmost edge of the driving shelf, allowing the entirety of the stake to be driven smoothly down into the ground adjacent the face of a form board. In a preferred form the stake includes reinforcing flanges extending from the underside of the driving shelf to an upper end of the shank, the flanges terminating short of the outer ends of the driving shelf.

FIELD OF THE INVENTION

The present invention is in the field of stakes used to support concrete forms or barriers that are used along the outside of an area in which concrete is to be poured, so as to contain the poured concrete in that area.

BACKGROUND AND DESCRIPTION OF RELATED ART

Concrete form stakes are typically used to secure wooden boards or “forms” around the perimeter of a concrete pouring area, the stakes driven partway into the ground along the outside face of a form to hold it securely in place before, during, and after the pouring operation. Known stakes come in many shapes and sizes, for example homemade stakes made from scrap wood at the construction site as well as different types of commercial stake made from wood, plastic, and metal.

Another type of stake used in concrete pouring operations is known as a screed stake, used in spaced pairs to hold screed rods or bars in an even plane across the area to be poured to ensure that the concrete is level and smooth.

My earlier U.S. Pat. No. 6,588,164, issued Jul. 8, 2003, discloses a stake especially adapted for use as a screed stake, but which can also be used as a form stake. This screed/form stake has a flat rear face and a U-shaped upper cradle portion extending from the front face of the stake, the cradle designed to mate with a separate driver. The driver also has a flat rear face, and a screed-rod-shaped portion that extends from the front face of the driver to mate with a screed rod groove in the cradle portion of the stake. When the lower end of the driver is mated with the stake's upper cradle, the upper end of the driver serves as a pounding surface to drive the stake into the ground. The upper surface of the screed-rod-shaped portion of the driver can be used as a screed rod elevation-measuring surface when seated in the cradle, providing a platform for a transit to measure whether the stake has been pounded in far enough to support a screed rod at the proper height. The screed/form stake has holes formed along its face for securing it to a concrete form with screws or nails. When used as a form stake, the stake is driven home with the same driver used for screeding operations, with the flat back of the driver allowing it to be used against the face of the form without interference. As shown in the patent, the stake can be driven to a point where its cradle is below the upper surface of the form. The stake is typically removed from the exterior face of the form after the concrete has been poured and has set.

I have a co-pending U.S. patent application Ser. No. 10/957,348 filed Oct. 2, 2004 for a stake designed specifically for use as a form stake. The stake can be pounded or driven into the ground with any non-specialized driving tool, such as a hammer or mallet or even a boot, and naturally levels itself at the top of the concrete form when pounded with such a tool. When the form is no longer needed, the stake can be easily pulled out of the ground with fingers or the claw of a hammer or tool. The form stake has a relatively wide, flat body with a flat rear face, and a forward-facing T-shaped flange structure extending from the front face of the stake. The T-shaped flange structure has a horizontal driving shelf with a uniform, level impact surface at the top of the stake, and a central vertical rib section extending downwardly from the driving shelf with a depth equal to the depth of the shelf protruding beyond the face of the stake. The driving shelf forms the top surface of the stake. The vertical rib bisects the stake. In a preferred form, the underside of the driving shelf has a predominantly perpendicular or acutely-angled surface on both sides of the central rib for grasping with the fingertips or hooking with a tool to pull the stake out of the ground. Although the form stake is lighter and less expensive to manufacture than my previous screed/form stake, it is easier and faster and stronger to use as a form stake.

Perhaps the most common type of concrete form stake is a simple nail stake, which looks and functions like a giant nail, except that it typically has a number of holes formed along the shank of the nail for securing it to a wooden form board.

Nail type stakes are often used for other purposes, most notably as tent stakes, since they easily penetrate even the hardest ground. When used as tent stakes, nail stakes are sometimes provided with a cross-piece frictionally held in place on the upper end of the shank below the nail-head to provide a pull handle and a place to tie guy-lines from the tent.

BRIEF SUMMARY OF THE INVENTION

The present invention is a form stake with a narrow ground-penetrating shank terminating at its upper end in a wider, horizontal, integral driving shelf that allows the stake to be pounded or driven into the ground with any non-specialized driving tool, such as a hammer or mallet or even a boot, and naturally levels itself at the top of the concrete form when pounded with such a tool. When the form is no longer needed, the stake can be easily pulled out of the ground with fingers or the claw of a hammer or tool. The driving shelf has a wide, uniform, level impact surface at the top of the stake, the preferably cylindrical ground-penetrating shank extending downwardly from the center of the driving shelf and tangentially aligned with a flat, rear, form-abutting edge of the driving shelf. In a preferred form, the shank has a diameter or width equal to the front-to-back depth of the driving shelf. The outer ends of the driving shelf extend freely beyond and above the shank body.

In a further form of the invention, the underside of the driving shelf has a pair of opposing force-transferring flanges extending downwardly and inwardly at an acute angle to an upper end of the shank. The flanges are thin-walled and centered on the underside of the driving shelf. In a preferred form, the flanges extend from an intermediate portion of the underside of the driving shelf, such that the outer ends of the shelf extend beyond the uppermost portions of the flanges.

In a further form of the invention, the shank portion of the stake is cruciform in section, with the force-transferring flanges merging into two side ribs of the cruciform shank.

The present form stake is lighter and less expensive to manufacture than my previous form stake, is easier and faster to use as a form stake, and is less likely to wander or cant when driven into hard ground.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of two form stakes according to the invention, one prior to being driven into the ground against a wooden form, and the other driven in level with the top of the form.

FIG. 2 is a front elevation view of a stake as shown in FIG. 1.

FIG. 3 is a side elevation view of the stake of FIG. 1, partially driven into the ground against the outside face of a concrete form.

FIG. 4 is a side elevation view similar to FIG. 3, but with the stake fully driven into position adjacent the concrete form.

FIG. 5 is a top plan view of the stake of FIG. 4 driven into the ground against the face of the form, with the shank portion of the stake shown in hidden lines.

FIG. 6 is a side elevation view similar to FIG. 3, but shows the stake being pulled from its fully driven position by hand.

FIG. 7 is a perspective view of a stake similar to the stake in FIGS. 1-6, but with a cruciform shank.

FIG. 7A is top plan view of the stake of FIG. 7, with the cruciform shank section shown in hidden lines.

DETAILED DESCRIPTION OF THE INVENTION

Referring first to FIGS. 1 and 2, the invention is illustrated in a first illustrative example as form stake 10. Stake 10 is preferably molded as one piece from a suitably strong plastic material, for example a nylon or ABS plastic, although other plastics and materials such as wood or metal can be used, and although the stake is not limited to one-piece construction. Stake 10 is used to laterally secure a wooden form 12 in place around an area in which concrete 13 is to be poured. As shown in the Figures, stake 10 is driven into the ground with its rear surface against the outer face of form 12 to prevent the form from shifting during pouring or curing of the concrete against the opposite inner face of form 12. The length of stake 10 can vary from under a foot to several feet in length, but in the illustrated embodiment is on the order of twelve to fourteen inches in length.

Stake 10 has a cylindrical ground-penetrating shank 16 terminating at its upper end in a flat, horizontal driving shelf 18 formed as an integral part of the stake, whether by molding, welding, mechanical attachment, or some other method for giving the driving shelf 18 a permanent, non-rotating, fixed driving connection to shank 16. The lower end of shank 16 preferably terminates in a point 16 a that helps the shank penetrate hard ground.

As best seen in FIGS. 2 through 4, driving shelf 18 has a flat top surface 18 a, a flat bottom surface 18 b, a rear edge 18 c flush at 17 with the tangentially rear-most portion 16 b of shank 16, and a front edge 18 d flush at 17 with the tangentially front-most portion 16 c of shank 16. Driving shelf 18 extends beyond both sides of shank 16, in the illustrated embodiment having a width (for example, 2.875 inches) at least three times the diameter (for example, 0.875 inches) of shank 16. The flat top surface 18 a of driving shelf 18 forms the upper end of the stake, with a surface area greater than the cross-sectional area of shank 16. As best shown in FIG. 5, when stake 10 is viewed from above, the relatively wide, flat, upper face 18 a of driving shelf 18 is the only visible surface, overlying the circumference of shank 16, and therefore presenting a significantly greater driving face. FIG. 5 shows the tangential or flush alignment of the rear-most and front-most vertical edges or surfaces 16 b, 16 c of shank 16 with the rear and front edges 18 c and 18 d of the driving shelf, allowing the form-facing side of stake 10 to present a smooth, unbroken sliding face to form 12 as stake 10 is driven into the ground against the form until the rear edge 18 c of the driving shelf is against the form. While a perfectly smooth, flat, uniform upper surface 18 a is preferred, it will be understood that minor variations such as different textures or surface finishes or patterns that leave the upper surface generally flat relative to the driving force and the top of the concrete form are acceptable. It will be understood that if both the rear and front edges 16 b and 16 c of the shank are flush with the rear and front driving shelf edges 18 c and 18 d as shown in FIG. 5, stake 10 can be used reversibly against form 12.

The junction of the upper end of shank 16 and the lower surface of driving shelf 18 is reinforced with angled fillets or flanges 20 extending from intermediate portions of the underside of the driving shelf to the sides of the upper end of shank 16, centered on the underside of the driving shelf 18 in alignment with the long axis of the shelf. Flanges 20 are preferably molded in one piece with the rest of stake 10. Flanges 20 are also preferably thin-walled, as illustrated, allowing an essentially tangential connection to the sides of shank 16, and providing room for fingers or a tool to grasp the underside of shelf 18 in the vicinity of the flanges. Flanges 20 efficiently transfer driving force from regions of the driving shelf 18 on either side of shank 16 into the shank, reducing stress at the junction of shelf and shank, and helping to keep the shank driven straight down even when the driving force is off-center.

Referring to FIGS. 3 and 4, stake 10 can be pounded into the ground with any non-specialized tool, for example the illustrated mallet 30, since the upper driving surface 18 a of the stake is a flat, wide, uniform force-distributing surface. No specialized driving tool is necessary, and, in soft soil, foot and even hand pressure (with body weight behind it) may be used to push against the relatively wide, even surface of the driving shelf. Driving the stake with non-specialized tools is accordingly both effective and comfortable, whether using a hammer, a mallet, a rock, a board, a boot, a hand, or any other convenient implement.

As best shown in FIGS. 1 and 4, stake 10 tends to automatically level itself both vertically and side-to-side at the upper surface 12 a of form 12, since a non-specialized driver (especially a driver with a driving or impact face wider than the depth of shelf 18) will tend to hit the upper surface 12 a of the form when the flat upper surface 18 a of driving shelf 18 is even with the upper surface of the form. Assuming that the overall length of stake 10 allows a sufficient portion of the stake to be driven into the ground for good holding power relative to the ground, leaving the stake's upper end 18 approximately even with the upper edge of form 12 provides the strongest possible support for the form. Leaving the upper surface of the stake 10 even with the top of form 12 also ensures that concrete smoothing tools can be run across the top of the form without interference. The overall jobsite is also given a neater, more professional appearance with all form stakes driven in evenly against the forms. And the risk of overdriving the form stake to a point where it becomes difficult to remove from the ground is reduced or eliminated.

Referring next to FIG. 6, stake 10 is also easily pulled out of the ground when the concrete forming operation is done. The lower surface or underside 18 b of driving shelf 18 is preferably perpendicular to the shank 16 of stake 10 so that maximum pulling force can be exerted on the stake through the shelf with the fingers or a tool hook or claw, as shown. The lower surface 18 b can also be angled inwardly at an acute angle to the front face of stake 10 (not shown), for an even better hooking action on the shelf when the stake is being pulled from the ground. While the lower surface 18 b is preferably flat and uniform as shown, it is possible to vary the contour so long as significant gripping or hooking portions are perpendicular or acute.

Holes 22 through shank 16 allow the stake to be secured to the face of form 12 in known manner, for example with nails or screws driven through holes 22 into the face of the form. Holes 22 preferably pass through shank 16 perpendicular to rear and front edges 18 c and 18 d of shelf 18, and therefore perpendicular to a form 12 being supported by a driven stake 10. Holes 22 could also be acutely angled, but angles greater than 45° tend to put nails or screws inserted through the holes at an ineffective angle relative to the face of form 12.

Referring to FIG. 6, although the thin walls of flanges 20 leave room for fingertips to hook the underside 18 b of shelf 18 on either side of the upper end of shank 16, upper portions of flanges 20 extend only partway toward outer ends 18 e of the shelf, allowing fingers or a hooking tool to wrap fully under (and even around the outer ends of the shelf 18 when the shelf reaches a point higher than form 12) for a better grip, as shown in phantom. This gives the person removing stake 10 the ability to exert both a very strong vertical pulling force, but also creates a moment arm relative to the shank body to provide side-to-side leverage to rock or loosen the shank to help free the stake from difficult ground. This is useful where the stake becomes firmly lodged in the ground, for example if a rough shank surface finish or holes 22 attract concrete dust or moist or compacted dirt or snow that can cement or freeze the stake into the ground.

Referring next to FIGS. 7 and 7A, a modified version of stake 10 is illustrated at 100, having a cruciform-section shank 116, a driving shelf 118 essentially the same as shelf 18 in FIGS. 1-6, and force-transferring flanges 120 similar to previously-described flanges 20. The cruciform shank 116, centered under driving shelf 118 and having a narrow, ground-penetrating body, will generally be lighter than cylindrical shank 16 if made from the same material, and may have some advantage in penetrating and holding in certain types of soil. The diameter of shank 116 and its relationship to driving shelf 118 is preferably similar to that of shank 16 and shelf 18, with the same tangential alignment of the rear and front ribs 116 c and 116 d with the rear and front edges 118 c and 118 d of driving shelf 118, and the same proportion of shelf width to shank diameter. The side ribs 116 e of shank 116 lend themselves to being extended to form (or to merge with) flanges 120 at the upper end of the shank.

It will be understood that while the circular and cruciform shanks 16 and 116 illustrated above are currently preferred, other cross-sectional shapes are possible, provided that at least the central rear edge or tangent of the shank body centered relative to drive shelf 18 is flush or tangential with the center of the rear form-facing edge 18 c of shelf 18. It will also be understood that while a rectangular shelf 18 is preferred, other symmetrical shapes with a flat rear form-facing edge are possible. And while the illustrated embodiments show single front and rear vertical edges or surfaces of the shank body aligned with the front and rear edges of the driving shelf 18, it is possible to align multiple front and rear edges of surfaces of a shank body with central portions of the front and rear edges of driving shelf 18, for example by rotating the cruciform shank body 116 of FIGS. 7 and 7A approximately 45°.

It will be understood that the length and width and relative dimensions of shank 16 and driving shelf 18 can vary according to the anticipated height of the forms with which it will be used, the nature of the ground into which stake 10 will be driven, and the weight or force of concrete that is anticipated against the form.

While stake 10 is especially designed for use as a form stake, it may find use in other applications for providing good holding power against significant forces in loose soil or sand or even snow.

It will be understood that the disclosed embodiment is representative of a presently preferred form of the invention, but is intended to be illustrative rather than definitive of the invention. The scope of the invention is defined by the following claims. I accordingly claim: 

1. A form stake comprising a narrow vertical shank body terminating in a wider flat horizontal driving shelf, the shank body having a rearmost vertical edge or surface tangentially aligned with a center portion of a rear form-facing edge of the driving shelf, the driving shelf being perpendicular to and centered over the vertical shank, the driving shelf having a flat, uniform upper driving surface overlying the vertical shank, and the driving shelf having outer ends spaced from the shank body such that fingers or a hooking tool can be placed on either side of the upper end of the shank body for removing the stake from a driven position.
 2. The form stake of claim 1, further comprising a pair of force-transferring flanges, one flange on each side of the shank body, the flanges extending from an underside of the driving shelf at an acute angle into contact with an upper end of the shank body.
 3. The form stake of claim 2, wherein the flanges have a thickness less than the front to back depth of the driving shelf, such that a finger or hooking tool can grasp or hook the underside of the shelf between a forward edge of the shelf and the flanges.
 4. The form stake of claim 3, wherein the flanges extend on the underside of the driving shelf only partway toward the outer ends of the driving shelf, such that at the outer ends of the driving shelf a finger or hooking tool can grasp or hook the entirety of the underside of the driving shelf at the outer ends.
 5. The form stake of claim 1, wherein the entirety of the shank body is located underneath the driving shelf.
 6. The form stake of claim 5, wherein a frontmost vertical edge or surface of the shank is tangentially aligned with a center portion of a front-facing edge of the driving shelf. 